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emk/kernel/src/sys/acpi.c

122 lines
No EOL
2.9 KiB
C

/* EMK 1.0 Copyright (c) 2025 Piraterna */
#include <sys/acpi.h>
#include <boot/emk.h>
#include <lib/string.h>
#include <util/log.h>
#include <sys/kpanic.h>
static int acpi_uses_xsdt = 0;
static void *acpi_rsdt_ptr = NULL;
static uint8_t acpi_checksum(void *ptr, size_t len)
{
uint8_t sum = 0;
uint8_t *data = (uint8_t *)ptr;
for (size_t i = 0; i < len; i++)
{
sum += data[i];
}
return sum;
}
static int acpi_validate_rsdp(acpi_rsdp_t *rsdp)
{
return acpi_checksum(rsdp, sizeof(acpi_rsdp_t)) == 0;
}
static int acpi_validate_xsdp(acpi_xsdp_t *xsdp)
{
if (acpi_checksum(xsdp, sizeof(acpi_rsdp_t)) != 0)
return 0;
if (acpi_checksum(xsdp, xsdp->length) != 0)
return 0;
return 1;
}
void acpi_init(void)
{
if (!rsdp_response || !rsdp_response->address)
{
kpanic(NULL, "No RSDP provided");
}
acpi_rsdp_t *rsdp = (acpi_rsdp_t *)rsdp_response->address;
log_early("RSDP found at %p", rsdp);
if (strncmp(rsdp->signature, "RSD PTR ", 8) != 0)
{
kpanic(NULL, "Invalid RSDP signature");
}
if (rsdp->revision >= 2)
{
acpi_xsdp_t *xsdp = (acpi_xsdp_t *)rsdp;
if (!acpi_validate_xsdp(xsdp))
{
kpanic(NULL, "XSDP checksum validation failed");
}
acpi_uses_xsdt = 1;
acpi_rsdt_ptr = (void *)(uintptr_t)xsdp->xsdt_address;
}
else
{
if (!acpi_validate_rsdp(rsdp))
{
kpanic(NULL, "RSDP checksum validation failed");
}
acpi_uses_xsdt = 0;
acpi_rsdt_ptr = (void *)(uintptr_t)rsdp->rsdt_address;
}
/* Validate RSDT/XSDT header */
acpi_sdt_header_t *sdt = (acpi_sdt_header_t *)acpi_rsdt_ptr;
if (acpi_checksum(sdt, sdt->length) != 0)
{
kpanic(NULL, "RSDT/XSDT checksum validation failed");
}
log_early("ACPI initialized, using %s at %p",
acpi_uses_xsdt ? "XSDT" : "RSDT", acpi_rsdt_ptr);
}
void *acpi_find_table(const char *name)
{
if (!acpi_rsdt_ptr || !name)
return NULL;
acpi_sdt_header_t *sdt = (acpi_sdt_header_t *)acpi_rsdt_ptr;
uint32_t entries;
if (acpi_uses_xsdt)
{
entries = (sdt->length - sizeof(acpi_sdt_header_t)) / sizeof(uint64_t);
}
else
{
entries = (sdt->length - sizeof(acpi_sdt_header_t)) / sizeof(uint32_t);
}
for (uint32_t i = 0; i < entries; i++)
{
acpi_sdt_header_t *table;
if (acpi_uses_xsdt)
{
uint64_t *xsdt_entries = (uint64_t *)(sdt + 1);
table = (acpi_sdt_header_t *)(uintptr_t)xsdt_entries[i];
}
else
{
uint32_t *rsdt_entries = (uint32_t *)(sdt + 1);
table = (acpi_sdt_header_t *)(uintptr_t)rsdt_entries[i];
}
if (strncmp(table->signature, name, 4) == 0)
{
if (acpi_checksum(table, table->length) == 0)
{
return table;
}
}
}
return NULL;
}